Arrangement for transforming a. rotating movement into a. striking or hammering movement



Sept. 16, 1930. E. H. w. WEIBULL 1,776,057

' ARRAN'G NT FOR TRANSFORMING A ROTATING IOVEMENT O A STRIKING OR MIERI IOVEIBNT Filed Nov. 19

Patented Sept. 16, 1930 UNITED STATES PATENT OFFIC ERNST HJ'ALMAR WALODDI WEIBULL, OF SALTSJOBADEN, SWEDEN, ASSIGNOB '10 AKTIEBOLAGET NORDISKA ABMATUBFABBIKERNA, OF STOCKHOLM, SWEDEN, A

LIMITED COMPANY ARRANGEMENT FOR TBANSFORMING A. ROTATING MOVEMENT INTO A. S'IBIKIIIG OB HAMMEBING MOVEMENT Application. filed November 28,1927, Serial No. 236,352, and in Sweden December 21 1828.

The present invention relates to a mechamsm for the converslon of rotary movement into astriking movement and differs from known arrangements of this kind by the fact that the recoil movement of the striking bod is effected by its striking against the anvil or the like to-whichthe' striking force is transmitted and not, as hitherto, for instance, by the co-operation of a rotating motor driven part itself.

According to a generic form of this invention a striking body sliding axially for instance on the motor driven rotating part or shaft is provided with an oblique striking face which in one end osition of the striking body co-operates wit an oblique striking face arranged on an anvil or the like, and with an energy storing device associated or co-operatin with the strikin body, said storing device being supplied with the whole or part of the energy necessary for the next strlkingmovement on the recoil of the rotating striking body from the oblique strikingrface of the anvil.

ig. 1 is a dia ammatic elevation of the driving shaft, striking body, anvil and associated parts of an arrangement for transforming rotary movement into a striking or hammering movement in accordance with the invention.

Fig. 2 is an axial section in detail through a practical embodiment of the invention,

partly broken away.

Fig. 3 is an end elevation of the anvil. 36 Fig. 4 is an end view of the striking body. F'g. 5 is a fragmentary side elevation of the anvil.

Fig. 6 is a side elevation of a part of the strikm body. Fi is an elevation of the striking body and driving shaft.

Figs. 8 and 9 are axial sections through modifications of the invention.

In Figs. 17 1 is the drivin shaft provided wlth a guide groove 2, w ch may be shaft 4 taking into said groove. The driving straight or for instance of the shape shown in Fig. l. The striking body 3 slides on the driving shaft 1 and in its axial movement along the driving shaft, is forced to follow the guide groove 2 by means of a bolt or shaft 1 has its face end provided with or connected to a guide journal 7 extending into the anvil 6 and the latter is mounted to slide in a suitable frame part 5 but prevented from turning therein by means of awedge 12. At the ends directed towards 'each other, the striking body 3 and the anvil 6 according to this invention are provided with one or more oblique strikin faces 8 and 9. .For the storing of energy the striking body 3 is connected with the driving shaft by means of a tension spring 10, which has one end attached to the bolt 4 and the other end to a bolt 11 inserted in the end of the drivin shaft.

On the shaft 1 being rotated by the electric motor, the striking body 3 will be forced to partake into this rotation by means of the olt 4 extending into the groove 2. If starting, at this occasion, from that position, the 7 striking body 3 occupies its rear position, in which the energy storing device 1s charged, following operation will take place.

The striking body will be advanced to wards the anvil and at the same time it will be rotated at a very great speed. When, at a this time, the oblique faces 8 of-the striking body 3 strike against the oblique faces 9 of the anvil 6, a shock or a strike will be transmitted to the anvil, the magnitude of this shock or strike being, at this event, dependent on the axial movement as well as on the rotating one of the striking body. The rotating movement of the striking body will, besides, efiect such a cooperation between the oblique faces 8 and 9 located on the striking body and the anvil respectively that the striking body, utilizin a portion of the rotating energy supplie to the striking body 25 I a bolt 4 secured to the striking ody 3 and by the electric motor, will be imparted a rapid .recoiling movement against the in v fluence of the energy storing device, which issupplied with ener y from the striking bod; Thus, the recoi 'ng movement of the stri 'ng body will be gradually stopped. The

' striking body will then once more be thrown energy storing device.

forwards by the influence of the energy,

. stored in the energy storing device, and, after this, the same operation will be repeated. Thus, the striking body will receive its recoiling movement by the energy absorbed from the motor at the moment the shock or the strike occurs, whilst the forward-move,- ment ofthe striking body is efiected by the In order in conjunction with the above stated operation to obtain a shockless: running of the ,driving shaft, certainconditions must be complied with, as hereinafter briefly set forth by reference to Fig. 1.

In the form of the inventlon above referred to the axial bearingrin the motor-driven rotating part 1 is constituted by an inclined or spiral groove 2 in said rotating art and by engaging with said, groove 2 or vice versa.

The pitch H of the spiral groove 2 in the rotating power actuated part 1 (the driving shaft) may be expressed by the formula 1' being the radius of the driving shaft 1 and a the angle of inclination of the groove. Accordingly the inclination k of the oblique striking ace 9 of the anvil 6 may be ex pressed by 1 h=21r1ieinaand Rtnfl h B being the angle of inclination of, the

oblique striking face and R the mean radius;

If the striking operation is efiected without any friction and the varying force between the striking weight and the anvil is =1) and acts on the mean radius R the energy im- If this impulse is divided into an axial com onent is, and a tangential component kg, t en k f= k cos )9 and the momentum of In; I I kpR k Sin 3.12

If m is the mass of the striking body and I its'moment of inertia with regard to the axis of rotation and '0 and IQ), the-velocity of translation ofthe striking body before and after the'shock, and Q0 and Q0 the corresponding angular velocities of the striking body then if '0 is assumed to be negative and 1:, positive there is: (I) 1)= 0 fl I(w,-w )=k,R=k sin 6.1%

' If :0 is the angular velocity of the driving shaft, the condition for shocklefss run mng 1n the sleeve is 'wr' w i 1 wz= o 'vz From II is obtained I 2 x l l I w we wr z) which inserted into (I) is m(v,-v k c'osfl 21.1 (v,- v 10 em 8,13

and by division 52L; 21.1 Rmc but Y Rmc? h" 21.1 h and i 41=I -wr If the striking operation takes place under friction, themedium friction may be determined by the angle of friction If the same deduction as above is carried'out there is, as will be readily seen m mom From this it is clear that if the shape of the striking body 3 is determined, i. e. if the j values r m and I are chosen, the inclination H of the groove in the driving shaft 1 will solely be determined for a certain value of the inclination h of the striking face 9 of the anvil 6, and this withoutdependence on the striking velocity o viz independent of the striking capacity of the striking body and out shocks during the time the striking body .does not touch the anvil.

body is connected with the driving shaft,

has no influence upon the shockless running. For a certain number of revolutions of the driving shaft a variation of the spring tension will instead only cause a change in the number of strokes of the striking body, a stronger spring increasing the number of strokes.

By means of an arrangement according to this invention the number of strokes may be changed by a simple exchange of springs and by a suitable ad ustment of the number of revolutions of the driving shaft and the spring tension, the number of strokes and,

thus, the striking capacity may be adjusted to the conditions claimed foreach special purpose of use.

From the formula it is also clear that if the moment of inertia is made very great and the angle of inclination of the striking face is constant the angle of inclination of the groove in the driving shaft approaches 90 VIZ w =w =w In this case the movement of the striking body 3 in relation to the driving shaft 1 will therefore be axial, while, if on is smaller than 90, the axial movement of the striking body 3 is combined with a peripheral movement as explained above.

Further it is not necessary to guide the striking body 3 peripherally by means of a groove 2 or journal or wedge as aforesaid, but this guide may be carried out in many other ways. So, for instance, the striking body ma be constructed as a nut and the rotary sha sleeve or the like as a correspondingly threaded spindle or vice versa. Further the rotation of the motor need not necessarily be transmitted to the striking body, compulsorily as above, but in an elastic man-. ner by the s ring-device if this is connected with the str' 'ng body and the driving shaft in such a way that the spring at the recoil movement of the striking body will not only store energy y axial contracti'on or expansion but also by torsion.

As storers for the energy of translation of the striking body during the recoil movement many other devices than springs may, of course, be suggested. For instance, the striking body may be a movable part of an air compressor. v

If as already stated, a combined axial and peripheral guide is used for the strikingxbody in such a. manner that a smaller num r of revolutions on the recoil movement is obtained than durin the movement-in the opposite direction, t are will besides shockless running, beflthe advantage that the ehergy storer will not have to absorb all the energy necessary for the stroke since this energy, in such an arrangement is due to a great part to the energy absorbed from the striking body by the decrease of the angular velocity, to

which the striking body is exposed when changing from striking movement to recoil movement. When suitably dimensioned this last mentioned part of energy may amount to of the total energy claimed for the stroke. According to the present invention it is suitable to provide for that the whole of the striking face of the hammer or of the anvil or both, is constituted by a single cam-like surface or by continuous cam-like surfaces so that at the moment of impact of the hammer or the anvil the contact is always between opposing oblique surfaces, whereby both the rotary and the translatory motions of the hammer are utilized for generating the striking movement imparted to the tool carried by the anvil.

In the embodiment shown in Fig. 8, 1 is the driving shaft, 2 the guide ooves therein and 3 the striking body apted in this case to slide in the hollow end of the driving shaft, said striking body being again provided with trunnions 4 taking into the ide grooves 2. 6 is the anvil sliding in the rame part 5, and provided with oblique striking aces 9 co-operating with corresponding strikin faces 8 on the striking body 3.

e stora e of energy during the recoil movement of the striking body3 is effected by compression of air in a chamber 14 located behind the striking body 3 in the hollow end of the driving shaft.

The embodiment in Fig. 9 differs from that shown in Figs. 2-7 in that the grooves 2 on the driving shaft 1 consist of screw threads in the end of driving shaft 1, cut at a suitable inclination, the storage spring being a compression spring 10 confined in a manner similar to Fig. 2. p

Itis to be pointed out that with the expression oblique strikin face is to be understood all such faces y means of which the rotating striking body 3 may be given its recoil movement. Thus the oblique striking faces on the striking body and/or the anvil 6 may be curved, for instance spherical.

Having now particularly described the nature of my invention and the manner of its operation, what I claim is:

1. A mechanism of the class described for the conversion of rotary movement into a striking movement com rising an axially reciprocating striking bo y, rotatin means for im arting rotary movement to said body, an oblique striking face on said body, an axially movable sliding anvil, an oblique counter face on said anvil presented for engagement by the oblique striking face, an ener storing device cooperating with the str' adapted to be supplied with energy for a onthe rotating means and an oblique strikstriking movement of the striking body by the recoil movement of the rotating stri ing body effected by the coaction between the oblique strikin face of the rotary striking body and the 0 lique striking face of the anvil at the moment the strike takes place.

2. An arrangement as claimed in claim 1 including means for effecting peripheral movement of the striking body relative to 10 the rotating means during axial reciprocation of the striking body. Y

3. An arrangement as claimed in claim 1 including means for effecting a spiral movement of the striking body relative to the rotating means during axial reciprocation of.the striking body. 4. An arrangement as claimed in claim 1, including a spiral guide for the striking body ing face on the anvil of an inclination such as to result, in the absence of friction, in ll I angular position of the striking 'bodyrela- -tive to the anvil.

6. A mechanism of the class described for the conversion of rotary movement into a striklng movement, including an axially reciprocating striking body, rotating means for imparting rotary movement to said body, an

axially movable and non-rotatable sliding anvil, an oblique counter face on said anvil presented. for engagement by the oblique strikln face, an energy stormg device. cooperating with the striking bod and ada' ted to be supplied with energy or a stri ing movement of the striking body by the recoil movement of the striking body effected by the coaction between the oblique striking face of the striking body and the oblique counter face of the anvil at the moment of engagement.

7. A mechanism of the class described, in-

peripheral movement of the striking body relative to the rotating means during axial reciprocation of the striking body.

8. A mechanism of the class described, including an axially reciprocable striking body, means for imparting rotary movement to said body, an anvil mounted for axial movement imparted thereto by the striking body, an energy storing'device associated with the striking body and adapted to be rotated incident to the recoil movement of the striking body, and means for effecting I a spiral movement of the striking body relative to the rotating means during axial re- I anvil to cause recoil of'the striking body, and

an energy storin device rotated during re-' coil-movement o the striking body to effect the following striking movement of the latter.

10. In combination, a non-rotatable anvil,-

a rotary driving" element, a reciprocable striking body rotated by the driving element, cam means acting incident to en gement of the rotating striking body wit the anvil to cause recoil of the striking body, and an energy storing device rotated durin recoil movement of the striking body to e feet the following striking movement of the latter, and means connectin the driving element with the striking body permitting limited rotation of the latter relative to'the driving element during recoil movement. I 11. In combination, a non-rotatable anvil, a rotary driving element, a reciprocable striking body rotated by the driving element, cam means acting incident to on agement of the rotating striking body-wit 'the anvil to cause recoil of the striking body, and an energystorin devicerotated durin recoil movement of t e striking body to e feet the following striking mov'ement ofthe latter, and means connectin the driving element with the striking b0 y permitting limited rotation of the latter inopposition to the energy storing device relative to the driving element during recoil movement.

ERNST. HIM-IA! WALODDI WEIBULL eluding. an axially reciprocable striking 7 body, means for imparting rotary movement to said body, an anvil mountedfor axial movement imparted thereto by the striking bod an ener device associated wit the striking body and adapted to be rotated incident to the recoil movement of the striking body, and means'for effecting III 

